This invention relates to overload protection or safety coupling devices for robotic tooling and of the general type disclosed in U.S. Pat. No. 4,954,005 which issued to the assignee of the present invention, and also as disclosed in U.S. Pat. No. 4,842,114 and No. 4,540,331. Such a safety or protection device is used between the end of an arm of a robot and the tooling carried by the arm and provides for opening an electrical control circuit to the shut down of the robot in the event the predetermined movement of the tooling by the robotic arm is accidentally blocked by an obstruction or by non-compliant movement of the robot arm due to a malfunction of the robot.
With any such safety or protection device, it is desirable for the device to operate and open the control circuit quickly in the event there is any rotational and/or tilting and/or axial movement of the tooling relative to the end of the robot arm. It is also desirable for the device to reset automatically with high return accuracy after the blockage is removed or the reason for the relative movement between the arm and the tooling is corrected. It has also been found desirable for the device to be compact with a low profile and have a high load capacity so that the robot arm may quickly move tooling having substantial size and weight or mass. While the safety or protection devices disclosed in the above patents provide some of the above desirable features, the devices have limitations which prevent the devices from providing all of the desirable features.